Automotive washer system utilizing a freezable washer liquid and a freeze-resistant washer liquid

ABSTRACT

A washer system which includes a first reservoir containing a freezable washer liquid and having a drain port therein. The drain port is in fluid communication with the freezable washer liquid when the first reservoir is in at least a full state. The washer system also includes a temperature sensor for measuring a critical temperature corresponding to approximately a freezing temperature of the freezable washer liquid, a drain plug sealingly communicating with the drain port, and an electrical control unit in operative communication with the temperature sensor and the drain plug. The electrical control unit controls the drain plug to drain the liquid from the first reservoir in response to the critical temperature.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. patentapplication Ser. No. 09/947,051 [Attorney Docket No. 200-1304/FGT 1467PA] filed Sep. 5, 2001.

BACKGROUND OF INVENTION

[0002] Technical Field

[0003] The present invention relates generally to a washer systemparticularly suited for automotive vehicles and more particularly to amethod and an apparatus for dispensing a freezable washer liquid or afreeze-resistant washer liquid depending on a given measuredtemperature.

[0004] Currently, most washer liquids contain volatile organic compounds(VOCs), such as alcohols or glycols, to depress the overall washerliquid freezing point temperature. The most common washer liquid is asolution of methyl alcohol (methanol) by weight in demineralized water,including a small amount of detergent and dye.

[0005] After having been dispensed onto the vehicle surface to becleaned, the volatile organic compounds contained in the washer liquidcan evaporate into the atmosphere. With sufficient atmospheric warmthand sunlight, such as during a hot and sunny day, certain VOCs,including those used as freezing point depression agents in washerliquid, may participate in a complex series of photochemical reactionsin the atmosphere leading to the formation of ozone, a major componentof smog (air pollution). For this reason, many governments have placedlimits on total allowable vehicular VOC emissions, primarily withrespect to engine exhaust and fuel delivery systems. As regulationsbecome increasingly restrictive, VOC emissions from washer systems maybe counted against total vehicular VOC emissions, though this currentlyis not the case.

[0006] Although reduction of VOC emissions is not addressed, U.S. Pat.No. 5,261,254 uses water extracted from the air in its washer system.The '254 patent is a windshield washer system that contains threeseparate reservoirs. One reservoir is used to collect water from theair. Another reservoir is used to hold an anti-freeze solution. Finally,the third reservoir is used to combine the water extracted from the airwith the antifreeze solution creating a freeze-resistant washer liquid.

[0007] U.S. Pat. No. 5,946,763 is a windshield washer system that alsocontains three reservoirs, although the reduction of VOC emissions isagain not addressed. One reservoir contains collected rainwater. Asecond reservoir contains anti-freeze solution. A third reservoircontains a strong cleaning agent. According to the level of freezeprotection needed, the anti-freeze solution is pumped into the tankholding the rainwater to create a washer liquid that isfreeze-resistant. The '763 patent describes a method of mixing therainwater with the anti-freeze upon determining the outside temperature,the washer liquid temperature, and the density of the washer liquid.Both the '763 and '254 patents transfer liquids from one reservoir toanother and to the spray nozzles via a pump, a pump in combination withtubing, or via gravity. Both patents provide a single reservoir and pumpassembly that is used to hold and distribute the washer liquid to thevehicle surface to be cleaned. In addition, both patents describesituations when water will be distributed throughout various reservoirs,pumps, tubing, passages and nozzles. When the temperature drops belowthe freezing point of water (0° C.), some of these components may freezeshut, thereby disabling the washer systems. Although the '763 patentdescribes a method of creating an ideal freezing point solution, it usessignals from several sensors in determining when to add anti-freeze tothe washer liquid. The '763 patent uses a sensor to measure temperatureof the washer liquid, a sensor for measuring the outside temperature,and a sensor for measuring the density of the washer liquid. The use ofthree sensors and various other components causes the '763 patent to berelatively complex and costly to produce.

[0008] Disadvantages associated with the systems disclosed in the '763and '254 patents include freezing in the portion of the washer systemthat distributes washer liquid, when the washer liquid therein has afreezing point greater than or equal to the surrounding temperature. Inaddition, since only one washer liquid reservoir and pump assembly isprovided, once the water is mixed with the anti-freeze solution to formthe washer liquid, the only washer liquid option available is afreeze-resistant mixture. When outside temperatures transition to alevel where ozone formation is possible, such as from a cold day orregion to a hot day or region, the freeze-resistant mixture is stillused, thereby emitting VOCs that are known contributors to ozone andsmog formation.

[0009] It would therefore be desirable to provide a washer system thatdispenses a washer liquid that emits a reduced amount of VOCs overconventional washer systems and that does not become inoperative due tofreezing of the washer liquid.

[0010] In dual or multiple systems, the reservoir containing freezableliquid must permit many freeze-thaw cycles without rupture. It wouldtherefore be desirable to provide a washer system that provides afail-safe reservoir for freezing and expansion cycles, and which doesnot become inoperative due to freezing of the freezable washer liquid.

SUMMARY OF INVENTION

[0011] One object of the invention is to reduce the amount of VOCemissions from the washer system of an automotive vehicle. Anotherobject of the invention is to provide a washer system that is functionalat all vehicle-operating temperatures.

[0012] In one aspect of the invention, a washer system includes a firstreservoir containing a washer liquid that, containing little or no VOC,may freeze at or below 0° C., such as a solution of water and soap, anda second reservoir containing a freeze-resistant washer liquid, such asa solution of water, alcohol, and soap. The first reservoir isfluidically coupled to a first pump. The second reservoir is fluidicallycoupled to a second pump. The first pump is fluidically coupled to afirst port. The second pump is fluidically coupled to a second port. Anelectronic control circuit is electrically coupled to the first pump andthe second pump. The electrical control circuit controls the first pumpand the second pump upon measuring a temperature.

[0013] In a further aspect of the invention, a method for operating awasher system comprises the steps of: measuring a temperature, drawing awasher liquid from a first reservoir when the measured temperature isgreater than a predetermined temperature, drawing washer liquid from asecond reservoir when the measured temperature is less than apredetermined temperature, and dispensing the washer liquid onto asurface.

[0014] Furthermore, the present invention may also take intoconsideration space constraints by incorporating at least a portion ofthe automotive washer system into an engine cooling fan shroud.

[0015] In another aspect of the invention, a washer system is providedwhich includes a first reservoir containing a freezable washer liquidand having a drain port therein. The drain port is in fluidcommunication with the freezable washer liquid when the first reservoiris in at least a full state. The washer system also includes atemperature sensor for measuring a critical temperature corresponding toapproximately a freezing temperature of the freezable washer liquid, adrain plug sealingly communicating with the drain port, and anelectrical control unit in operative communication with the temperaturesensor and the drain plug. The electrical control unit controls thedrain plug to drain the liquid from the first reservoir in response tothe critical temperature.

[0016] In another aspect of the invention, a washer system is providedwhich includes a first reservoir containing a freezable washer liquidand having a drain port therein in fluid communication with thefreezable washer liquid when the first reservoir is in at least a fullstate. A drain plug sealingly communicates with the drain port, and athermal actuator is coupled to the first reservoir and is in operativecommunication with the drain plug. The thermal actuator controls thedrain plug to drain the liquid from the first reservoir in response to acritical temperature.

[0017] One advantage of the invention is that the washer system reducesthe amount of emitted VOCs over prior known systems while preventing thesystem from being disabled by freezing temperatures. Another advantageis that the invention minimizes the use of complicated systemcomponents, thereby reducing production costs.

[0018] The present invention itself, together with further objects andattendant advantages, is best understood by reference to the followingdetailed description, taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF DRAWINGS

[0019]FIG. 1 is a perspective view of an automotive vehicle having awasher system according to the present invention.

[0020]FIG. 2 is a schematic view of the first washer system according tothe preferred embodiment.

[0021]FIG. 3 is a flow chart illustrating a method, describing operationof the invention for the first washer system of FIG. 2.

[0022]FIG. 4 is a schematic view of the second washer system accordingto the preferred embodiment.

[0023]FIG. 5 is a perspective view of the second washer system in FIG.4.

[0024]FIG. 6A is a schematic view of the third washer system accordingto the preferred embodiment.

[0025]FIG. 6B is a schematic view of a thermostat switch that may beused in the third washer system shown in FIG. 6A.

[0026] FIGS. 7-9 are schematic views of alternate fail-safe embodimentsfor the first reservoir.

DETAILED DESCRIPTION

[0027] In each of the following figures, the same reference numerals areused to refer to the same components. While the present invention isdescribed with respect to an automotive washer system, the followingwasher systems are also capable of being adapted for other applicationssuch as a windshield washer system, a head lamp or tail lamp washersystem, and a washer system for the rear window in a vehicle.

[0028] Referring to FIG. 1, a perspective view of an automotive vehicle10 having a washer system 12 according to the present invention isillustrated. Automotive vehicle 10 has a windshield 14 and wiper blades16. A command switch 18 is located within vehicle 10. Actuating thecommand switch 18 causes the washer system 12 to pump washer liquid ontothe windshield 14 and at the same time actuate the wiper blades 16 bypowering a wiper motor (not shown). This in turn washes and cleans thewindshield 14 (or other surfaces) on the vehicle 10. The command switch18 may be of any style commonly used for a washer system in anautomotive vehicle, such as stalk-mounted, console-mounted, orinstrument panel-mounted.

[0029] Referring now to FIG. 2, a first embodiment of the washer system12 is shown. The washer system 12 has a first reservoir 21, a secondreservoir 23, and a fluid distribution circuit 26. The fluiddistribution circuit 26 directs washer liquid from either the firstreservoir 21 or the second reservoir 23 to an exit circuit 28 wherewasher liquid is dispensed. The exit circuit 28 directs washer liquid toa surface to be washed, such as the windshield 14 of FIG. 1. Theelectronic control module (ECM) 20 determines whether to use the washerliquid in the first reservoir 21 or the second reservoir 23. The ECM 20may comprise analog or digital logic control devices or may bemicroprocessor based. Upon determining which washer liquid to use, theECM 20 controls the fluid distribution circuit 26, directing theappropriate washer liquid through the exit circuit 28 and onto thewindshield 14. When the command switch 18 is closed, the ECM 20generates a command signal to activate the washer system 12, such thatthe system mode is equal to “activate”. After the command switch 18 isopened, the ECM 20 discontinues the command signal, such that the systemmode equals “deactivate”.

[0030] The first reservoir 21 is illustrated as having six sides 22,similar to a cube (top side 22 a, left side 22 b, right side 22 c, andbottom side 22 d are shown). Of course, other shapes and irregularshapes may be used due to packaging constraints in the vehicle. Thefirst reservoir 21 has a filling hole 32 in the top side 22 a with aremovable lid 34. The bottom side 22 d has an opening 36 to which adrain tube 38 may be connected. The first reservoir 21 contains afreezable washer liquid 40, such as a solution of soap and water, thathas a freezing point temperature similar to pure water. The reservoir 21is designed to hold the freezable washer liquid 40 in the liquid stateand in the higher volume solid state. A water-based liquid solution mayexpand up to about 10% by volume when transforming from a liquid stateto a solid state. To compensate for the higher volume, the firstreservoir 21 may contain an expandable bladder 42 at least partiallysurrounded by foam 44. The expandable bladder 42 is designed to expandup to the inner volume of the first reservoir 21 minus the volume of theisolation foam 44 surrounding the bladder 42, upon compression of saidfoam. The foam 44 or similar compressible material isolates and locatesthe bladder 42 within the first reservoir 21 and allows for theexpansion of the water-based liquid 40 without generating significantstrain on the sides 22 of reservoir 21, thus preventing fracturing ofthe sides 22. The foam 44 also prevents the bladder 42, and any solid orliquid contained there within, from swinging freely and striking thesides 22 of reservoir 21 during vehicle movement, thus mitigating apotential source of noise. Of course, other known methods forcompensation of ice formation would be evident to those skilled in theart, including the use of an expansion resilient plastic reservoir.

[0031] The second reservoir 23 also is illustrated as having six sides24, similar to a cube (top side 24 a, left side 24 b, right side 24 c,and the bottom side 24 d are shown). As mentioned above, other shapesmay be used. The second reservoir 23 contains a freeze-resistant washerliquid 48, such as a solution of water, alcohol (VOC) and soap. Thesecond reservoir 23 also has a filling hole 50 through top side 24 awith a removable lid 52. The bottom side 24 d has a drain tube 58 thatprotrudes through a seal 54.

[0032] Referring now to FIGS. 2, 2A, and 2B, the fluid distributioncircuit 26 is fluidically connected to the first reservoir 21, secondreservoir 23 and a fluid purge apparatus 61, and is electricallyconnected to the ECM 20. The three operative components of the fluiddistribution circuit 26 include a first dual-purpose valve 62, a pump66, and a second dual purpose valve 70 that are coupled in series.“Dual-purpose” refers to the capability of drawing washer liquid or gas(air) into the fluid distribution circuit 26. The first dual-purposevalve 62 is preferably a solenoid actuated valve with selectable openingof four flow ports 62 a, 62 b, 62 c and 62 d, as best shown in FIG. 2A.Unless selectively energized to open, each of the flow ports 62 a, 62 b,62 c and 62 d is normally closed.

[0033] The pump 66 is a liquid pump with an inlet side 66 a and anoutlet side 66 b. The pump 66 may of the type and size suitable for theparticular application. The second dual-purpose valve 70 is preferably asolenoid actuated valve with selectable opening of three flow ports 70a, 70 b and 70 c, as best shown in FIG. 2B. Unless selectively energizedto open, each of the flow ports 70 a, 70 b and 70 c is normally closed.The fluid distribution circuit 26 also includes a number of fluidconnections such as: fluid drain tube 38, fluid drain tube 58, fluidpassage tube 64, fluid passage tube 68, and an exit circuit 28. Thefluid connections may be formed of tubes, or if contained in a singlehousing, as passages or channels therethrough. The drain tube 38protrudes through a seal 55 in the bladder 42 and is coupled between thebladder 42 and the first dual-purpose valve flow port 62 a. The draintube 58 protrudes through a seal 54 and is coupled between the bottomside 24 d and the first dual-purpose valve flow port 62 b. The firstdual-purpose valve flow port 62 c is connected to a pump inlet 66 a bytube 64. The pump outlet 66 b is connected to the second dual-purposevalve flow port 70 a by tube 68. The second dual-purpose valve flow port70 b is connected to an exit circuit 28. The fluid exit tube 72 iscoupled between the second dual-purpose valve flow port 70 b and anozzle 74. Although, only one nozzle is illustrated, multiple nozzlesmay be contemplated in an operational embodiment.

[0034] A fluid movement sensor 76, such as a pressure sensor or a flowrate sensor, is connected to the tube 68 via tube 69. The fluid movementsensor 76 measures the movement of the freezable washer liquid beingpumped from the first reservoir 21. Of course, other types of movementsensors may be used. The first reservoir 21 may contain a first liquidlevel sensor 89 and the second reservoir 23 may contain a second liquidlevel sensor 91.

[0035] The fluid purge apparatus 61 includes a fluid passage tube 78, agas/liquid separator 80, a fluid passage tube 82, and a vacuum tank 84.The gas/liquid separator 80 has an inlet 80 a and two outlets 80 b and80 c. The second dual-purpose valve flow port 70 c is connected to thegas/liquid separator inlet 80 a by fluid passage tube 78. The gas/liquidseparator outlet 80 b is connected to a vacuum tank 84 by fluid passagetube 82. The vacuum tank 84 draws washer liquid into the gas/liquidseparator 80. The gas/liquid separator 80 dispenses the washer liquiddrawn into it through the gas/liquid separator outlet 80 c. The firstdual-purpose valve 62, passage tube 64, pump 66, passage tube 68, thesecond dual-purpose valve 70 and the exit circuit 28 comprise theportion of the fluid distribution circuit 26 that is purged by the fluidpurge apparatus 61. The fluid purge apparatus 61 also purges the fluidmovement sensor 76.

[0036] An ECM 20 is used to electrically control the operation of thewasher system 12. The ECM 20 is electrically coupled to, and receiveselectrical signals from, the fluid movement sensor 76, a temperaturesensor 86, the liquid level sensor 89, the liquid level sensor 91 andthe command switch 18. The temperature sensor 86 may be any of thefollowing but is not limited to: a bi-metal thermostat switch, a solidstate thermostat switch, a temperature gage, a thermocouple, athermistor, or any other temperature measuring device. The ECM 20 isalso electrically coupled to the first dual-purpose valve 62 and thesecond dual-purpose valve 70, the pump 66, the vacuum tank 84, and awarning light 87. The ECM 20, upon receiving signals from the fluidmovement sensor 76, the temperature sensor 86, the liquid level sensor89, the liquid level sensor 91 and the command switch 18, controls thefirst dual-purpose valve 62 and the second dual-purpose valve 70, thepump 66, the vacuum tank 84, and the warning light 87.

[0037] The ECM 20 monitors the last liquid used (either 40 or 48), thesystem mode (either “activate” or “deactivate”), the temperature sensor86, the first liquid level sensor 89 and the second liquid level sensor91. In FIG. 2, if the level of the liquid contained in either reservoir21 or reservoir 23 is physically below the corresponding liquid levelsensor, the ECM 20 activates a warning light 87 to warn the motoristthat the corresponding liquid is running low. However, upon command, theECM 20 may continue to draw liquid from reservoir 21 or reservoir 23until either reservoir runs dry, depending on the temperature, as willbe described later.

[0038] Referring now to FIG. 3, the operation of the first embodiment ofthe first washer system 12 is best described in the flow chart shown.The operation is initialized in step 88.

[0039] In step 90, the first reservoir 21 and the second reservoir 23are filled at the vehicle assembly plant, the first reservoir 21 with afreezable washer liquid 40, such as water or a solution of soap andwater, and the second reservoir 23 with a freeze-resistant washer liquid48, such as a solution of water, alcohol and soap. Prior to leaving theplant, the washer system 12 is operated to prime the washer pump 66 andexit circuit 28. To prime the pump 66, the command switch 18 is closed,where after the ECM 20 opens flow ports 62 a and 62 c of the firstdual-purpose valve 62 and flow ports 70 a and 70 b of the seconddual-purpose valve 70, and actuates the pump 66 to flow freezable washerliquid from the first reservoir 21 through pump 66 into the exit circuit28.

[0040] In step 92, the ECM 20 operation liquid state variable “A” is setto a pre-set value of zero. The ECM 20 has two operating liquid states:A=0 representing that the prior liquid state was freezable washer liquid40 or A=1 representing that the prior liquid state was freeze-resistantwasher liquid 48.

[0041] In step 94, the ECM 20 determines the air temperature or thetemperature of any relevant vehicle component, such as the windshield 14via the temperature sensor 86.

[0042] The temperature is compared to a critical temperature(T_(critical)), which in this case is set to 5° C. [41° F.]. Thetemperature T_(critical) corresponds to the temperature where freezingof pure water may be possible, plus a safety factor. When thetemperature is greater than T_(critical) step 96 may be executed. Whenthe ECM 20 determines the temperature is less than or equal toT_(critical), step 100 is executed.

[0043] In step 96, when the system mode equals “activate”, step 112 isexecuted. Step 112 and subsequent steps are discussed later.

[0044] In step 100, when the fluid distribution circuit 26 is primedwith freezable washer liquid 40, operating state is A=0, step 102 isexecuted.

[0045] In step 102, at least a portion of the fluid distribution circuit26 is purged. The purging of the freezable washer liquid 40 prevents thewasher liquid from freezing in at least a portion of the fluiddistribution circuit 26. To accomplish the purging of the fluiddistribution circuit 26, the ECM 20 selectively opens the flow ports 62c and 62 d between the atmosphere and the pump 66, the seconddual-purpose valve flow ports 70 a, 70 b and 70 c between the pump 66,the exit circuit 28, and the gas/liquid separator 80. This allows thevacuum tank 84 in the purging apparatus 61 to draw all the fluidcontained within a portion of the fluid distribution circuit 26 into thegas/liquid separator 80 so the distribution circuit is effectivelydrained, at which time the aforementioned valve flow ports are closed bythe ECM 20.

[0046] Referring back to step 100 above, if on the other hand the fluiddistribution circuit 26 contains freeze-resistant washer liquid 48(A=1), then step 104 is executed.

[0047] In step 104, the fluid distribution circuit 26 remains primedwith freeze-resistant washer liquid 48. Upon finishing either step 102or step 104, step 106 may be executed.

[0048] In step 106, when the system mode equals “activate” step 108 isexecuted.

[0049] In step 108, when the temperature is less than or equal toT_(critical) step 110 is executed.

[0050] In step 110, the ECM 20 upon receiving the temperature signalautomatically uses the freeze-resistant washer liquid 48 from the secondreservoir 23 since the previous liquid usage state was A=1. To drawfreeze-resistant washer liquid, the ECM 20, only while receiving acommand signal from command switch 18 in step 106, opens flow ports 62b, 62 c, 70 a, and 70 b while simultaneously energizing pump 66. Uponsystem deactivation in step 111, step 116 is executed.

[0051] In step 116, A is reset to A=1, after which the ECM functionreturns to step 94. When the temperature remains at or below thefreezing point of water (0° C.) for extended periods of time, some orall of the freezable washer liquid 40 in the first reservoir 21 maysolidify.

[0052] In step 108, when the temperature becomes greater thanT_(critical) step 112 is executed.

[0053] In step 112, the ECM 20 attempts to draw freezable washer liquid40 from the first reservoir 21 and then executes step 114.

[0054] In step 114, as long as the ECM 20 senses, via the fluid movementsensor 76, a fluid pressure downstream of pump 66 that is within apre-selected pressure range P_(critical) (or flow rate within apre-selected range F_(critical)), then step 118 is executed. In thisexample a pressure sensor is used in place of the fluid movement sensor76.

[0055] In step 118, the ECM 20 draws freezable washer liquid 40 from thefirst reservoir 21 until the system mode equals “deactivate” in step119, at which time step 120 is executed.

[0056] In step 120, liquid state variable A is reset to A=0 anddistribution circuit 26 is primed with freezable washer liquid 40. Uponcompletion of step 120, the ECM 20 function returns to step 94.

[0057] In step 114, as long as the ECM 20 receives a signal from thefluid movement sensor 76 that is not within a pre-selected pressurerange P_(critical) (or flow rate range F_(critical)), which may occurwhen some or all of the freezable washer liquid 40 in the firstreservoir 21 has solidified into ice 46, step 122 is executed. In step122, the ECM 20 checks the liquid and solid (if any) level in the firstreservoir 21 via liquid level sensor 89. When the level is above apredetermined low limit level, step 110 is executed. The ECM 20 revertsto step 110 to draw freeze-resistant washer liquid 48 from the secondreservoir 23. If the system mode returns to “deactivate” in step 111(command switch 18 is opened), then step 116 is executed. In step 116,the ECM 20 resets liquid state variable A to A=1 and returns to step 94.

[0058] In step 122, when the freezable washer liquid 40 and/or ice 46 inthe first reservoir 21 are at or below the predetermined low limit levelas determined by liquid level sensor 89, step 124 is executed.

[0059] In step 124, the ECM 20 activates the warning lamp 87 andsimultaneously prevents the operation of the pump 66 until the firstreservoir 21 is filled above the predetermined low limit level, asdetermined in step 122. Thus, when the temperature is aboveT_(critical), the washer system will preferably only drawfreeze-resistant washer liquid 48 from the second reservoir 23 if thelevel of the freezable washer liquid 40 in the first reservoir 21 isabove the low limit level and the signal from the fluid movement sensor76 is not within a pre-selected pressure range P_(critical).

[0060] After the washer system 12 leaves the plant a variety oftemperatures may be encountered. As such, when the system mode equals“activate” the automatic use of liquid from either the first reservoir21 or the second reservoir 23 is based on the temperature signalreceived. When the temperature remains above T_(critical), freezablewasher liquid 40 may continue to be drawn from the first reservoir 21.When the temperature remains at or below T_(critical) then the freezeresistant washer liquid 48 may continue to be drawn from the secondreservoir 23. Whenever the washer system 12 is deactivated (commandswitch 18 is opened) the ECM 20 closes all possible flow paths byclosing all of the flow ports in the first dual-purpose valve 62 and thesecond dual-purpose valve 70, thus preventing fluid contained in thefluid distribution circuit 26 from draining into the first or secondreservoir by gravity.

[0061] Referring now to FIGS. 4 and 5, at least a portion of washersystem 12 may be incorporated into a vehicle engine-cooling fan shroud178 to form washer system 12′. Washer system 12′ reduces costs, reducesthe number of vehicle components, and utilizes space available invehicle 10. The first reservoir 21′ has a filler hole 32 with aremovable lid 34 at the top of the fan shroud 178. The second reservoir23′ has a filler neck 126′ with a filler hole 50 and removable lid 52 atthe top of the fan shroud 178. Reservoirs 21′ and 23′ form a hole 180 inthe center 177 of the fan shroud 178. The vehicle engine-cooling fan 179rotates inside hole 180 in the center of the fan shroud 178. To simplifythe installation of an expandable bladder 42 and the isolation foam 44(not shown) in the first reservoir 21′, it would be most practical toassemble the fan shroud 178 from two halves as best shown in FIG. 5showing a first half 182 and a second half 184.

[0062] Referring now to FIG. 6A, a third embodiment of the presentinvention illustrating washer system 12″, whereby the purging methoddescribed in the first and second embodiments is not utilized whilemaintaining a freeze resilient system. Preferably, the first reservoir21″ and the second reservoir 23″ are incorporated into a fan shroud178″. The first reservoir 21 ″ contains a freezable washer liquid 40.The first reservoir 21 ″ is designed to allow the freezable washerliquid to expand. The first reservoir 21″ may be produced from a freezeresilient plastic or may contain an expandable bladder 42 at leastpartially surrounded by foam 44 (neither shown) which protects thereservoir 21″ in case freezable washer liquid 40 solidifies andundergoes a 10% expansion by volume. The first reservoir 21 ″ also has afilling hole 32 in the top side 22 a″ with a removable lid 34 to closethe filling hole 32. The bottom side 22 d″ has a first outlet 187 towhich a first pump 188 may be connected.

[0063] The second reservoir 23″ contains a freeze-resistant washerliquid 48. The second reservoir 23″ also has a filling hole 50 in thetop side 24 a″ with a lid 52. The bottom side 24 d″ has a second outlet189 to which a second pump 192 may be connected.

[0064] The first pump 188 is connected to a first hose assembly 194. Thefirst hose assembly 194 is also connected to a first port 196 of a firstnozzle 198 and a first port 206 of a second nozzle 200. The first washerliquid path 201 comprises the first reservoir 21″, the first pump 188,the first hose assembly 194, the first port 196 of the first nozzle 198,and the first port 206 of a second nozzle 200. The second pump 192 isconnected to a second hose assembly 202. The second hose assembly 202 isalso connected to a second port 204 of the first nozzle 198 and a secondport 197 of the second nozzle 200. The first hose assembly 194 and thesecond hose assembly 202 may be produced from elastomeric or polymericmaterials capable of withstanding 10% volume expansions, in the eventthat the liquids in the hose assemblies freeze. The second washer liquidpath 207 comprises the second reservoir 23″, the second pump 192, thesecond hose assembly 202, the second port 204 of the first nozzle 198,and the second port 197 of the second nozzle 200. The first washerliquid path 201 is parallel to the second washer liquid path 207. Atemperature sensor 86 generates a temperature signal. A fluid movementsensor 76 generates a pressure signal (or flow rate signal). Liquidlevel sensors 89″ and 91″ generate liquid level signals for the firstreservoir 21″ and the second reservoir 23″, respectively. The first pump188, the second pump 192, the temperature sensor 86, the fluid movementsensor 76 and the liquid level sensors 89″ and 91″ are electricallycoupled to an electrical control circuit 205 comprising the ECM 20 andthe temperature sensor 86. The electronic control circuit 205 maycomprise: a microprocessor, a thermostat switch, a temperature sensor,or other electronic device that may be used to measure temperature orswitch between said first washer liquid path 201 and second washerliquid path 207.

[0065] At least a portion of washer system 12″″ is preferablyincorporated into a fan shroud 178′. The cross-sectional area of the fanshroud 178′ is divided into a first portion and a second portion. Thefirst portion is the first reservoir 21″, the second portion is thesecond reservoir 23″. An opening 180 is in the center 177 of thecross-sectional area of the fan shroud 178′. The engine-cooling fan 179rotates within the opening 180.

[0066] In operation, the ECM 20 actuates the first pump 188 if and onlyif the current system mode equals “activate” corresponding to the ECM 20receiving a signal from the command switch 18, the temperature (sensedby temperature sensor 86) is greater than T_(critical), and the pressuredownstream of the pump 188 (sensed by movement sensor 76) is within apre-selected pressure range P_(critical) . The temperature T_(critical)corresponds to a temperature below which pure water will solidify, plusa safety factor. During the time when the ECM 20 is activating the firstpump the ECM 20 does not actuate the second pump 192. Actuating thefirst pump 188 causes washer liquid in the first reservoir 21″ to bepumped through the first hose assembly 194 and dispensed out of port 196and port 206 onto the windshield 14.

[0067] The ECM 20 actuates the second pump 192 and at the same time doesnot actuate the first pump 188 if the system mode equals “activate” andthe temperature is less than or equal to T_(critical). Actuating thesecond pump 192 causes freeze-resistant washer liquid 48 in the secondreservoir 23″ to be pumped through the second hose assembly 202 anddispensed out port 204 and port 197 onto the windshield 14. In addition,the ECM 20 will actuate the second pump 192 and at the same time notactuate the first pump 188 if the system mode equals “activate”, thetemperature is greater than T_(critical), the washer liquid level in thefirst reservoir 21″ is higher than the predetermined low limit level asdefined by the position of the level sensor 89′ and the pressure sensedby fluid movement sensor 76 is not within a pre-selected pressure rangeP_(critical). Finally, even when the system mode equals “activate” andthe temperature is greater than T_(critical), the ECM 20 will notactuate the first pump 188 or the second pump 192 when the washer liquidlevel in the first reservoir 21″ is at or below the predetermined lowlimit level as defined by the position of liquid level sensor 89′ andthe pressure sensed by the fluid movement sensor 76 is not within apre-selected pressure range P_(critical).

[0068] Referring now to FIG. 6B, costs to produce washer system 12″ maybe reduced by eliminating the liquid level sensors 89′ and 91′, theliquid movement sensor 76, the temperature sensor 86 and the ECM 20. Inreplacement of temperature sensor 86 and ECM 20, a bimetal or solidstate thermostat switch 208 is used to sense temperature and selectivelydirects the command signal from command switch 18 to either pump 188 orpump 192, depending on the position of the thermostat switch 208, whichis a direct function of the temperature and the thermostat set point.The thermostat switch 208 set point is equal to T_(critical), whereT_(critical) is predetermined, preferably set in the range of 10° C. to21° C. When the temperature sensed by the thermostat switch 208 is aboveT_(critical), the command signal will be directed to pump 188 via thethermostat switch 208. When the temperature sensed by the thermostatswitch 208 is equal to or less than T_(critical), the command signal isdirected to pump 192 via the thermostat switch 208. The temperatureT_(critical) corresponds to the temperature where the freezing of purewater will occur (0° C.), plus a safety factor preferably ranging from10° C. to 21° C. The safety factor improves the likelihood that all ofthe freezable washer liquid 40 in the first reservoir 21″ and in thefirst washer liquid path 201 will be completely liquid (none in solidform, so as to block liquid flow) at any time the first pump 188 isactuated, thus ensuring the desired function.

[0069] Referring now to FIGS. 7-9, there are shown schematic views ofalternate failsafe embodiments for the first fluid reservoir 21. As thefirst fluid reservoir 21 contains freezable washer liquid, it isdesirable to have the first fluid reservoir 21 constructed such that itcan withstand repeated freeze-thaw cycles without rupture or to includemechanisms to prevent the freezeable washer liquid from damaging orbursting the reservoir. FIGS. 2 and 4 disclose at least two embodimentsfor the first fluid reservoir 21 which incorporate features to allow thereservoir to withstand repeated freeze-thaw cycles without rupture. Inparticular, the reservoir includes an expandable bladder 42 at leastpartially surrounded by foam 44. The expandable bladder 42 is designedto expand up to the inner volume of the first reservoir 21, less thevolume of the isolation foam 44 surrounding the bladder 42, uponcompression of the foam. The foam 44 or similar compressible materialisolates and locates the bladder 42 within the first reservoir 21 andallows for the expansion of the water-based liquid 40 without generatingsignificant strain on the sides of the first fluid reservoir 21, thuspreventing fracture or rupture of the reservoir.

[0070] The fail-safe designs of FIGS. 7-9 can alternately preventfracture or rupture of the first fluid reservoir 21 due to the expansionof the water-based liquid 40 contained therein. The principle of thefail-safe designs shown in FIGS. 7-9 is to reduce the amount offreezable liquid within the reservoir 21, when a critical temperaturehas been achieved, by an amount sufficient to allow the expansion of theremaining liquid without undue stress or strain on the body of thereservoir. Such failsafe mechanisms as described herein can also becombined with the forgiving, expandable designs of FIGS. 2 and 4.

[0071] In the following figures, the same reference numerals are used torefer to like components. To the extent a more detailed description ofthe component has been provided with reference to an earlier figure,reference should be made thereto. Referring now to FIG. 7, there isshown a schematic diagram of a first fail-safe embodiment of the firstfluid reservoir 21. Although the first fluid reservoir 21 is shown as asection of a cube-shaped volume, it should be understood that thereservoir can be of any shaped-volume, including integral designs suchas that shown in FIG. 4. Thus, the first fluid reservoir 21 includes afiller opening 32 and filler cap 34 for filling the reservoir with afreezable washer liquid 40 and sealing the reservoir, respectively. Thefreezable washer liquid 40, such as a solution of soap and water, has afreezing point temperature in the range of pure water, and expands up toabout 10% by volume when transforming from a liquid state to a solidstate. The bottom of the first fluid reservoir 21 includes an opening 36to which a drain tube 38 is connected for drawing fluid out of the firstfluid reservoir 21 as described above. A liquid level sensor 89 is alsoincluded as described above which is in operative communication with theECM 20. A temperature sensor 86 is also included as described abovewhich is also in operative communication with the ECM 20.

[0072] In addition, the fail-safe mechanism includes a drain port 240formed in the side of the first fluid reservoir 21 which is sealinglyengaged by plug 254. Under normal operating conditions, such as when thetemperature is above a critical temperature, the plug 254 seals thedrain port 240. The plug 254 is coupled to an actuator 250 by way of aconnecting rod 252. The actuator 250 may be a solenoid or relay and theconnecting rod 252 may be the armature of the solenoid. Otherelectrically-actuated mechanical drive arrangements for the plug 254 arealso contemplated and included in the present invention. The plug ispreferably a resilient elastomeric material such as plastic or rubber.The plug 254 can also be a threaded member cooperating with a threadedbore 240, or a valve in fluid communication with the drain port. Theactuator 250 is operatively coupled to, and controlled by the ECM 20. Atemperature sensor 260 may also be included and coupled to the firstfluid reservoir 21 to sense the temperature of the liquid 40 therein, orthe ambient temperature of the air about the first fluid reservoir 21.The sensor 260 is operatively coupled to the ECM 20 to provide suchtemperature information. Alternatively, temperature sensor 86 mayprovide sufficient temperature data to the ECM 20 to control thefail-safe mechanism.

[0073] In operation, when a critical temperature is sensed whichcorresponds to a temperature just above freezing, plus a safety factor,for the freezable washer liquid 40 within the first fluid reservoir 21,the actuator 250 is activated by the ECM 20 to retract the plug 254 fromthe drain port 240 and allow the liquid 40 to drain from the first fluidreservoir 21. The temperature data may be provided by the temperaturesensor 86 or sensor 260, if present. The drain port 240 is configured ata location within the side wall of the first fluid reservoir 21 to purgeenough of the liquid 40 such that, if the remaining amount of liquid 40were to subsequently freeze and expand, the first fluid reservoir 21would not be damaged. The duration of the actuator activation cancorrespond to a predetermined time, or continue until the level of fluid40 sensed by the liquid level sensor 89 reaches the desired level. Inthis regard, the predetermined time may correspond to a time sufficientfor the fluid 40 to reach the level of the drain plug 240 or, if thedrain plug is located at a level other than the desired, maximum levelof fluid, such as below the desired maximum level, to a time sufficientto ensure the desired maximum level will be met at the average flow rateof the fluid 40 through the drain port 240. Similarly, the liquid levelsensor 89 need not be at the same level as the drain port 240. Indeedthe drain port 240 can be located at the bottom of the first fluidreservoir 21, and the liquid level sensor 89 can be located to indicatethe maximum desired level of fluid.

[0074] In the example of FIG. 8, the actuator 250 and plug 254 arecontrolled by a thermocouple 260, in the form of a temperature sensor,coupled to the first fluid reservoir 21. The mechanical unit comprisingthe actuator 250, plug 254 and sensor 260 operate mechanically as afunction of the sensed temperature. Thus, they can operate independentlyof, and without need for, the ECM 20. All known thermally-activatedactuators are contemplated for the actuator 250 including, but notlimited to, shape memory alloys, bimetal disks, wax core thermostats, orbimetal or solid state thermostat switches. Providing such actuatorswith mechanical leverage, and calibrating such actuators at anappropriate temperature set point, the actuator 250 can open or seal thedrain port 240 as desired. The drain port 240 may remain open as long asthe temperature sensed is less than the critical temperature, or theactuator can be set to actuate for a predetermined period of time inresponse to sensing the critical temperature as described above.Alternatively, or in addition, the actuator 250 can be overridden by asignal from the ECM 20 to close the drain port 240 upon the fluid 40reaching a desired sensed level as determined by the fluid level sensor89.

[0075] In the example of FIG. 9, the actuator and plug mechanism areomitted. Instead, the opening 36 and drain tube 38 act as a drain port.A valve 270, in operative communication with the ECM 20, is activated inresponse to sensing the critical temperature. The temperature signal canbe provided, again, by a separate temperature sensor 260, or the sensor86 as described above. Upon activation, the valve 270 can permit fluidcommunication between the opening 36 and open conduit 272 to drain fluid40 from the first fluid reservoir 21. The valve 270 can be activated fora predetermined period of time or in response to a fluid level asdetected by fluid level sensor 89 described above. Alternatively, thevalve 270 can be omitted, and the fluid purge system 61 can be activatedto purge fluid from the reservoir 21 until the fluid 40 achieves adesired level, or for a predetermined period of time based upon the flowcharacteristics of the fluid 40 and size of the opening 36 andcapability of the purge system 61.

[0076] The above described washer systems, to one skilled in the art,are capable of being adapted for various purposes and are not limited tothe following automotive applications: a windshield washer system, ahead lamp or tail lamp washer system, and a washer system for the rearwindow in a vehicle. The above-described invention can also be variedwithout deviating from the true scope of the invention.

1. A washer system comprising: a first reservoir containing a freezablewasher liquid and having a drain port therein in fluid communicationwith said freezable washer liquid when said first reservoir is in atleast a full state; a temperature sensor for measuring a criticaltemperature corresponding to approximately a freezing temperature ofsaid freezable washer liquid; a drain plug sealingly communicating withsaid drain port; and an electrical control unit in operativecommunication with said temperature sensor and said drain plug, saidelectrical control unit controlling said drain plug to drain said liquidfrom said first reservoir in response to said critical temperature.
 2. Awasher system according to claim 1 wherein said temperature sensor iscoupled to said first reservoir and measures a temperature of saidfreezable washer liquid.
 3. A washer system according to claim 1 whereinsaid temperature sensor measures a temperature of ambient air proximatethe first reservoir.
 4. A washer system according to claim 1 whereinsaid drain port is located at a fluid level corresponding toapproximately an amount of freezable washer liquid that can freezewithout damaging said first reservoir.
 5. A washer system according toclaim 1 comprising an actuator coupled to said drain plug and inoperative communication with said electrical control unit, saidelectrical control unit controlling said actuator to open said drainplug and drain said liquid from said reservoir in response to saidcritical temperature.
 6. A washer system according to claim 5 whereinsaid electrical control unit controls said actuator to open said drainplug for a predetermined period of time in response to said criticaltemperature.
 7. A washer system according to claim 1 comprising a fluidlevel sensor for providing a fluid level signal, said fluid level sensorcoupled to said first reservoir, and wherein said electrical controlunit controls said drain plug to drain said liquid from said reservoirin response to said critical temperature and said fluid level signal. 8.A washer system according to claim 7 wherein said fluid level sensorindicates a fluid level corresponding to approximately an amount offreezable washer liquid that can freeze without damaging said firstreservoir.
 9. A washer system according to claim 1 comprising a secondreservoir containing a freeze-resistant washer fluid and at least onepump fluidically connected to said first and second reservoirs, said atleast one pump being controlled by said electrical control unit inresponse to a temperature signal from said temperature sensor.
 10. Awasher system comprising: a first reservoir containing a freezablewasher liquid and having a drain port therein in fluid communicationwith said freezable washer liquid when said first reservoir is in atleast a full state; a drain plug sealingly communicating with said drainport; and a thermal actuator coupled to said first reservoir and inoperative communication with said drain plug, said actuator controllingsaid drain plug to drain said liquid from said first reservoir inresponse to a critical temperature.
 11. A washer system according toclaim 10 comprising a fluid level sensor for providing a fluid levelsignal, said fluid level sensor coupled to said first reservoir, andwherein said thermal actuator controls said drain plug to drain saidliquid from said reservoir in response to said critical temperature andsaid fluid level signal.
 12. A washer system according to claim 11wherein said fluid level sensor indicates a fluid level corresponding toapproximately an amount of freezable washer liquid that can freezewithout damaging said first reservoir.
 13. A washer system according toclaim 10 comprising a fluid level sensor for providing a fluid levelsignal and an electrical control unit in operative communication withsaid fluid level sensor and said thermal actuator, said fluid levelsensor coupled to said first reservoir, and wherein said thermalactuator opens said drain plug to drain said liquid from said reservoirin response to said critical temperature and said electrical controlunit closes said drain plug in response to said fluid level signal. 14.A washer system according to claim 10 wherein said drain port is locatedat a fluid level corresponding to approximately an amount of freezablewasher liquid that can freeze without damaging said first reservoir. 15.A washer system according to claim 10 wherein said drain port is locatedproximate a bottom of said first reservoir and said thermal actuatorcontrols said drain plug to drain said liquid from said reservoir inresponse to said critical temperature for a predetermined period oftime.
 16. A washer system according to claim 10 comprising an electricalcontrol unit, a temperature sensor in operative communication with saidelectrical control unit, a second reservoir containing afreeze-resistant washer fluid and at least one pump fluidicallyconnected to said first and second reservoirs, said at least one pumpbeing controlled by said electrical control unit in response to atemperature signal from said temperature sensor.
 17. A washer system fora vehicle comprising: a first reservoir containing a freezable washerliquid and having a drain port therein in fluid communication with saidfreezable washer liquid when said first reservoir is in at least a fullstate; a second reservoir containing a freeze-resistant washer fluid; atleast one pump fluidically connected to said first and secondreservoirs, a temperature sensor for measuring a critical temperaturecorresponding to approximately a freezing temperature of said freezablewasher liquid; a fluid level sensor coupled to said first reservoir andproviding a fluid level signal; a drain plug sealingly communicatingwith said drain port; and an electrical control unit in operativecommunication with said fluid level sensor, said temperature sensor,said at least one pump and said drain plug, said electrical control unitcontrolling said drain plug to drain said liquid from said reservoir inresponse to said critical temperature and said fluid level signal, andsaid at least one pump being controlled by said electrical control unitin response to a temperature signal from said temperature sensor.
 18. Awasher system according to claim 17 wherein said drain port is locatedat a fluid level corresponding to approximately an amount of freezablewasher liquid that can freeze without damaging said first reservoir. 19.A washer system according to claim 17 wherein said drain port is locatedproximate a bottom of said first reservoir.
 20. A washer systemaccording to claim 17 wherein said fluid level sensor indicates a fluidlevel corresponding to approximately an amount of freezable washerliquid that can freeze without damaging said first reservoir and saidelectrical control unit opens said drain plug to drain said liquid fromsaid reservoir in response to said critical temperature and closes saiddrain plug in response to said fluid level signal.